Piston ring



JELBERT J. JENKINS, OF IMIIDLANDy MICHIGAN, ,ASSIGNOR T0 THE DOWCHEMICAL4 COMJPY, OIF MIDLAND, MICHIGAN, A CCRIORATION D'F MICHIGAN.

ris'ron nine.

Applicaton fleol September To all whom t may concern.'

Be it known that I, ELBERT J. JENKINS, a citizen of the United States,and a resident of Midland, county of Midland, and State of Michigan,have invented a new and' useful Improvement in Piston Rings, of whichthe following is a specification, the principle of the invention beingherein explained and the best mode in which I have contemplated applyingthat principle, so `as to distinguish it from other inventions. v i

liV am aware that so-called light metal alloys have been heretoforeIutilized with more or less success for the construction of pistons ininternal combustion engines.

Thus notably an alloy composed of aliiminum as a predominant ingredienthas been thus employed. I am notv aware, however, that such alloy, stillless an-"alloy of the particular composition hereinafter set forth, hasever been utilized to form the rings which are a-n essential feature inthe contruction of internal combustion engines; in

fact such an alloy composed principally of aluminum would not beentirely satisfactory for this purpose as it is not a good bearing metalin contact with the cast iron of the cylinder wall, and pistons composedof such an alloy require to be given more than the usual clearance forthis reason and because of other features ,such as a tendency -to growwhich such alloys show.

The objectv of the present invention accordingly is to provide a pistonring of light metal which will satisfactorily serve in the connectionstated, by reason fof its composition and construction. To theaccomplishment of this and related ends such piston ring then iscomposed of the ingredients and includes the structural featureshereinafter 'fully described and particularly set forth in theJ claims,the annexed drawing and the following description settin forth but oneof the various ways in which the principle of the invention .may beused.

In said annexed drawing f ig.v lis a central sectional view more or lessydiagrammatic in character illustrating a typical internal combustionengine e uipped with `my improved piston rings; ig. 2 is a similaki`section on a lar er scale showing one such ring together with theadjacent walls of a cylinder and piston, and Fig. '3 is a transversesection, i. e., in

2a, i920. serial No. 412,302.

the plane of such ring showing a portion of the ring with the vadjacentwalls of the cylinder and piston.

In its general features of construction, the internal combustion engineshown in the drawing is of familiar design, comprising a cast ironcylinder 1, the upper portion of which is provided with a suitable waterjacket 2 preferably integral therewith. Below the cylinder and enclosedin a suitable case 3 is a crank 4, which is connected by means of aconnecting rod 5 with a transverse pin 6 secured in the piston 7. Thespecific design of the latter forms no'part of the present inventionexcept that as previously indicated, such piston is formed of a lightmetal alloy. Preferablyv the prinl/cipal constituents of the alloy usedin such piston, just as in the case of the piston rings 8 presently tobe described, are inagnesium and aluminum, magnesium being the'rpredominating constituent. As most satisfactory for a piston thusdesigned for use in an internal combustion engine I find an alloycomposed of from 8 to 15 parts aluminum and the balance magnesium givesthe most satisfactory results, such alloy having a specific gravityyless than 2. The term light metal,l however, will .be understood tocomprehend any alloy in which the predominant constituent is aluminum(sp. gr. 2.7) or magnesium `(sp. gr. 1.72) or the two metals takentogether.

As just indicated, the composition of my improved piston rings 8 is thesame asthat given as constituting the preferred com osition of thepiston itself. It will be un erstood, however, that my improved pistonrings may be employed with other light metal pistons and for that matterwith the familiar cast iron piston that -is ordinarily j, used ininternal combustion engines, superior results being obtained in allcases.

Such rings are formed ,by casting a cylinder of the light metal alloy,such cylinder having proper internal and external diameters, cutting offa section of such cylinder to form a ring of the desired yheight andthen severing such ring at one point in its circumference.` The severedring may then be rolled, peened, or other-v wise manipulated to bringthe ends thereof into proper relation yand to give the ring thenecessary degree of resiliency to insure close fitting contact betweenthe same and iio' ' the cylinder wall when the ring is seated vringsordinarily used, so that the heat froml the piston, forming as thelatter does the go-between between the piston and the cylinder wall isquickly carried to the latter. Atthe same time the alloy rhaving thecomposition stated is not abrasive to cast iron and so insures that thecylinder wall will notbe scored from the action of such rings on anytype'of piston. The weight being small in comparison even with lightmetal pistons in which aluminum instead of magnesium is thepredominating ingredient, helps correspondingly to decrease the weightof the reciprocating parts, while the natural tension or resiliency ofthis special alloy is suflicient at all times to keep the rings in closefitting contact with the cylinder wall and so insuresl good compressionin the engine.

Other forms may be employed embodyl ing the features of my inventioninstead of the one here explained, change bein made in the form ofconstruction, provi ed the elements stated by any of the followingclaims or the equivalent of such stated elements be employed. c

I therefore particularly point out and distinctly claim as myinvention 1. As a new article of manufacture, a piston Aring for aninternal combustion engine composed of a light metal alloy, in

which the predominant constituent is magnesium.`

2. As a new article of manufacture, a piston ring for an internalcombustion engine composed of a light metal alloy, in which thepredominant constituent is magnesium and the principal remainingconstituent is aluminum.

3. In an internal combustion engine, the combination witha cast ironcylinder, of a pistontherefor composed of a light metal alloy, andpiston rings carried by said piston and likewise composed -of a lightmetal alloy, the predominant constituent of which is magnesium.

4. In an internal combustion en ine, the combination with a cast ironcylinder, of a piston therefor composed of a light metal alloy, andpiston lrings carried by said piston and likewise composed of av lightmetal alloy, the predominant constituent of which is magnesium, and theprincipal remaining constituent is aluminum. A

Signed by me this 20th day of September, 1920.

' ELBERT J. JENKINS.

